The FX3U-80MT/ES-A is Mitsubishi Electric’s 80-point transistor source output base unit for the MELSEC FX3U compact PLC series, providing 40 digital inputs and 40 PNP source transistor outputs in a self-contained AC-powered controller — the source (PNP) output counterpart to the FX3U-80MT/ESS sink model, delivering the highest transistor output I/O count in the FX3U base unit range for applications requiring PNP-compatible field devices and high-cycle 24 VDC load switching across 40 output points. As the largest source output model in the FX3U family, the FX3U-80MT/ES-A is the standard specification for European and Asian machine builders where PNP output polarity is the established wiring convention for sensors, actuators, and safety devices. Available now at Atlantech Drives with worldwide express delivery and 12-month warranty — complete our quote form for pricing and availability.
What Is the FX3U-80MT/ES-A?
The FX3U-80MT/ES-A is a MELSEC FX3U series compact PLC base unit with transistor source (PNP) outputs, providing 40 input points (X0–X47) and 40 transistor output points (Y0–Y47). The «ES-A» suffix designates source output type with AC power supply — the transistor outputs use PNP topology with a shared negative supply common, requiring the external 24 VDC load supply’s negative terminal to be connected to the output common, and the output transistors sourcing 24 VDC to the load terminal when activated. This is the direct complement to the FX3U-80MT/ESS sink model: where the ESS model connects positive supply to common and pulls to 0 V on activation (NPN/sink), the ES-A model connects negative (0 V) to common and pushes +24 V on activation (PNP/source). The designated high-speed output points Y0 and Y1 support pulse generation at up to 100 kHz for stepper and servo positioning — available on both source and sink transistor models with identical pulse performance. The FX3U CPU processes all programs at 0.065 µs per basic instruction with 64,000-step capacity, consistent across all FX3U base unit variants.
Key Technical Specifications
- Model: FX3U-80MT/ES-A
- Total I/O Points: 80 (40 inputs + 40 outputs)
- Input Type: 24 VDC sink (X0–X47)
- Output Type: Transistor source/PNP (Y0–Y47), 0.5 A per point, 5–30 VDC
- Output Polarity: Source (PNP) — common terminal to 0 VDC negative
- High-Speed Pulse Output: Y0 and Y1 up to 100 kHz; Y2 up to 10 kHz
- Power Supply: 100–240 VAC, 50/60 Hz
- Program Memory: 64,000 steps
- Execution Speed: 0.065 µs per LD instruction
- Built-in High-Speed Counters: 6 inputs (100 kHz)
- Communication: RS-422 (built-in)
- Real-Time Clock: Built-in
- Battery Backup: Yes
- Expansion: Up to 8 extension units, up to 4 special adapters
- Operating Temperature: 0°C to 55°C
- Dimensions (W × H × D): 220 mm × 90 mm × 87 mm
- Weight: Approx. 1.20 kg
Architecture & Design Overview
The FX3U-80MT/ES-A’s source output architecture implements PNP transistor switches with the collector connected to the 24 VDC positive supply rail and the emitter driving the output terminal — when the transistor switches ON, it sources current from the +24 VDC supply to the output terminal, through the load, and back to the 0 VDC common terminal. This current sourcing behaviour is compatible with NPN-input field devices that require a positive voltage at their input terminal to activate — the majority of European industrial sensors, solenoid valve controllers, and safety relay input modules use NPN (sinking) input circuits that are directly compatible with PNP source outputs without signal conditioning. The output common terminal of the FX3U-80MT/ES-A connects to the 0 VDC (negative) rail of the external 24 VDC load supply — confirming this connection polarity is the most critical wiring step when installing a source output model, as reversing the common polarity (connecting +24 V to the common terminal as in a sink model) will cause all outputs to be permanently active and will damage the output transistors. The FX3U-80MT/ES-A uses the same CPU board, program memory, and communication interface hardware as the FX3U-80MT/ESS sink model — the PNP versus NPN output type is implemented entirely in the output driver interface board, which is the only hardware difference between the two models.
Installation Advice
Before wiring the FX3U-80MT/ES-A output circuit, clearly mark the output common terminal polarity in the panel wiring documentation as 0 VDC (negative) — this is the single most common source of FX3U-80MT/ES-A installation errors, as engineers familiar with sink output models (ESS suffix, common to +24 VDC) may connect the source model’s common to +24 VDC by mistake, permanently damaging all 40 output transistors. Use different wire colours for the source output common (0 VDC) versus the sink output common (+24 VDC) if both model types are used in the same panel installation. For the 40 output load circuits, use 0.5 mm² wire minimum for each output point, with individual fusing or electronic protection for each output group to limit fault current and prevent cascade transistor damage if a field device short circuit occurs. Verify at commissioning that each output drives the correct load and that the load current does not exceed 0.5 A per point — use a clamp ammeter to measure the actual load current at maximum output duty cycle, as solenoid valves and relay coils with high inrush current can briefly exceed the 0.5 A rating during the initial activation transient if no current-limiting resistor is fitted. For the high-speed pulse outputs (Y0, Y1), verify that the stepper driver or servo amplifier’s pulse input circuit is compatible with PNP (source) output signals — some stepper drivers specify NPN (sink) pulse input only, requiring a signal polarity converter between the FX3U-80MT/ES-A output and the driver input.
Frequently Asked Questions
Q: Can the FX3U-80MT/ES-A source outputs drive NPN transistor input modules on a remote I/O station?
A: Yes. FX3U-80MT/ES-A PNP source outputs are directly compatible with NPN (sinking) inputs on remote I/O stations — the PNP output sources +24 VDC to the NPN input terminal, which is exactly what NPN input circuits require to activate. This compatibility between PNP source outputs and NPN sink inputs is the standard in European automation wiring practice and requires no signal conditioning.
Q: What is the electrical difference between the FX3U-80MT/ES-A and the FX3U-80MT/ESS in terms of field device compatibility?
A: The FX3U-80MT/ES-A (source/PNP) is compatible with NPN-input field devices — sensors and actuators where the input circuit activates when +24 VDC is applied to the input terminal. The FX3U-80MT/ESS (sink/NPN) is compatible with PNP-input field devices — sensors where the input activates when the input terminal is pulled to 0 VDC. In practice, European-standard wiring uses PNP sensors with NPN inputs on the PLC (ESS model), while some North American installations use NPN sensors that require PNP outputs (ES-A model) — verify the sensor output polarity before selecting the PLC output type.
Q: Does the FX3U-80MT/ES-A include protection against output short circuits?
A: The FX3U-80MT/ES-A transistor outputs include internal overcurrent protection that limits the output current and activates a fault flag in the event of a sustained short circuit — the protection circuit prevents immediate transistor damage in most short-circuit scenarios. However, the overcurrent protection is not instantaneous, and a very low impedance short circuit at the moment of output activation can cause a high transient current spike before the protection activates. External fusing at each output common group terminal (typically 4 A slow-blow per group) provides additional protection and is recommended for industrial panel installations.
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